Mitsubishi Lancer Evolution IX. Manual — part 634

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-49

STEP 3. Check whether the diagnosis code is
reset.

Q: Is diagnosis code 34 set?

YES :

Replace the SRS-ECU (Refer

to

P.52B-109

).

NO :

An intermittent malfunction is suspected
(Refer to GROUP 00

− How to Use

Troubleshooting/Inspection Service Points

P.00-5

).

Code No.35: Ignition of the air bag completed

DIAGNOSIS CODE SET CONDITIONS

This diagnosis code is set after the air bag has
deployed. If this diagnosis code is set before the air
bag has deployed, the cause is probably a malfunc-
tion inside the SRS-ECU.

PROBABLE CAUSE

Malfunction of the SRS-ECU

DIAGNOSIS

Replace the SRS-ECU. (Refer to

P.52B-109

).

Code No. 39 Air bags Deployed Simultaneously

DIAGNOSIS CODE SET CONDITIONS

This code is set when the air bags have deployed
simultaneously. If this code is set before the air bags
have deployed, an internal failure may have occurred
in the SRS-ECU.

PROBABLE CAUSE

Malfunction of the SRS-ECU

DIAGNOSIS PROCEDURE

Replace the SRS-ECU. (Refer to

P.52B-109

).

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-50

Code No.41: Power supply voltage (IG1 (A) voltage) drops abnormally.

OPERATION

• The SRS-ECU is powered from the ignition

switch (IG1).

• The SRS-ECU power is supplied from two cir-

cuits. Even if one circuit is shut off, the air bag
can inflate.

DIAGNOSIS CODE SET CONDITIONS

This diagnosis code is set if the voltage between the
IG1 terminals (fuse No.2 circuit) and earth is lower
than a predetermined value for a continuous period
of 5 second or more. However, if the system returns
to normal condition, code number 41 will be erased
automatically and the SRS warning lamp will go out.

PROBABLE CAUSES

• Damaged wiring harnesses or connectors

• Malfunction of the SRS-ECU

IGNITION
SWITCH (IG1)

POWER SOURCE
CIRCUIT

BACK-UP
CAPACITOR

D.C.-D.C.
CONVERTER

MICROCOMPUTER

COMBINATION
METER

WARNING LAMP
DRIVE CIRCUIT

Wire colour code
B : Black LG : Light green
G : Green L : Blue
W : White Y : Yellow
SB : Sky blue BR : Brown
O : Orange GR : Gray
R : Red P : Pink V : Violet

SRS-ECU

NOTE

: LH drive
vehicles
: RH drive
vehicles

IG1 Power Supply Circuit System

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-51

DIAGNOSIS PROCEDURE

STEP 1. Check junction block fuse number 2.

Q: Is the fuse burned out?

YES :

Go to Step 4.

NO :

Go to Step 2.

STEP 2. Voltage measurement at the SRS-ECU
connector C-12
(1) Disconnect the negative battery terminal.

(2) Disconnect SRS-ECU connector C-12.

(3) Connect the negative battery terminal.
(4) Turn the ignition switch to the "ON" position.

CAUTION

Do not insert a test probe into the terminal from
its front side directly as the connector contact
pressure may be weakened.
(5) Voltage measurement between C-12 harness

side connector terminal 16 and body earth.

OK: 9 V or more.

Q: Is the check result normal?

YES :

Go to Step 8.

NO :

Go to Step 3.

AC301761 AC

Fuse No.2

Junction
block

AC101950AJ

SRS-ECU

Harness side
connector
(rear view)

C-12 (Y)

Connector: C-12

AC203279

13 14 15 16 17 18 19 20

5 6 7 8 9 10 11 12

1 2

3 4

AF

C-12
Harness connector
(rear view)

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-52

STEP 3. Check the connectors between SRS-ECU
connector C-12 and ignition switch connector
C-208.

Q: Is the check result normal?

YES :

Check the harness wires for open circuit

between SRS-ECU connector C-12
(terminal No.16) and ignition switch
connector C-208, and repair if necessary.

NO :

Repair the defective connector.

AC101950AJ

SRS-ECU

Harness side
connector
(rear view)

C-12 (Y)

Connector: C-12

AC303806

Connector: C-208
<LHD>

Harness side
connector
(front view)

AI

Clock spring

AC303820 AE

Connector: C-208
<RHD>

Harness side
connector
(front view)

Clock spring

AC303823

Junction block (front view)

Connectors: C-211, C-214

C-214

C-211

AV

<RHD>

C-211

Harness side
(front view)

C-214

AC303809

Junction block (front view)

Connectors: C-211, C-214

C-211

Harness side
(front view)

C-214

C-211

AY

<LHD>

C-214